XIV.—The Absorption of Light by Inorganic Salts. No. XI.: Conclusion

1914 ◽  
Vol 33 ◽  
pp. 156-165
Author(s):  
R. A. Houstoun
Keyword(s):  
Special Reference ◽  
Present State ◽  
Light Wave ◽  
Wave Length ◽  
The Body ◽  
Inorganic Salts ◽  
Short Account ◽  
Absorption Of Light ◽  
Dispersion Of Light

In this paper a short account will be given of the present state of the theory of the absorption of light, with special reference to the results gained in this series of investigations.Theories of the dispersion of light may be divided into two classes: (1) those in which the body is regarded as consisting of particles which vibrate under the influence of the light wave; and (2) those in which the body is regarded as consisting of obstacles which diffract the light wave. According to (2), light is scattered, not absorbed; a wave going through the body diminishes in intensity, but the energy lost is radiated out laterally without change of wave-length.

scholarly journals On the absorption of light by crystals

1938 ◽  
Vol 167 (930) ◽  
pp. 384-391 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Wave Length ◽  
Short Wave ◽  
Point Of View ◽  
Theoretical Point ◽  
Lattice Vibrations ◽  
Short Wave Length ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Positive Hole

The purpose of this paper is to discuss the absorption of light by non-metallic solids, and in particular the mechanism by which the energy of the light absorbed is converted into heat. If one considers from the theoretical point of view the absorption spectrum of an insulation crystal, one finds that it consists of a series of sharp lines leading up to a series limit, to the short wave-length side of which true continuous absorption sets in (Peierls 1932; Mott 1938). In practice the lattice vibrations will broaden the lines to a greater of less extent. When a quantum of radiation is absorbed in the region of true continuous absorption, a free electron in the conduction band and a "positive hole" are formed with enough energy to move away from one another and to take part in a photocurrent within the crystal. When, however, a quantum is absorbed in one of the absorption lines , the positive hole and electron formed do not have enough energy to separate, but move in one another's field in a quantized state. An electron in a crystal moving in the field of a positive hole has been termed by Frenkel (1936) an "exciton".

THE SMUTS OF THE GENUS CINTRACTIA PARASITING KOBRESIA SPECIES

1961 ◽  
Vol 39 (1) ◽  
pp. 155-164 ◽  
Author(s):  
Ilkka Kukkonen
Keyword(s):  
Special Reference ◽  
Spore Germination ◽  
Modern Concept ◽  
Short Account ◽  
Host Genus ◽  
The Third

In this paper the modern concept of infection by species of Cintractia is briefly discussed. Three species are treated, two of which, C. elynae Sydow and C. kobresiae Mundkur, are redescribed, and the third is recognized as new, C. lindebergiae n. sp. The spore germination of C. elynae is described and illustrated. A short account of the host genus Kobresia is given with special reference to the species attacked by the above smuts.

scholarly journals A new method of spectrophotometry in the visible and ultra­violet and the absorption of light by silver bromide

1920 ◽  
Vol 97 (683) ◽  
pp. 181-190 ◽  
Keyword(s):  
Light Intensity ◽  
Photographic Plate ◽  
Wave Length ◽  
New Method ◽  
Silver Bromide ◽  
Selective Absorption ◽  
Quantitative Investigation ◽  
Advantages And Disadvantages ◽  
Absorption Of Light

A quantitative investigation of the absorption of light by silver bromide has been undertaken as a preliminary to a photochemical investigation of the action of silver bromide in the photographic dry plate. A good summary of the advantages and disadvantages of the various methods which have been devised by different experimenters for the quantitative investigation of the absorption of light by substances is given by Ewest in a thesis entitled, “Beiträge zur quantitativen Spectralphotographie,” of which an abstract is given by F. F. Renwick. All the methods which have been used previously either depend upon Schwarzschild’s law of the relation between time of exposure and the photographic effect, or a so-called neutral wedge is used which is supposed to absorb equally in all wave-lengths or is calibrated for selective absorption. The method which we have used is in some ways similar to that used by Ewest, but the apparatus required is very much simpler and a wedge of the material under examination is used instead of the neutral wedge of Ewest. In our method all that is required of the photographic plate is that the exposure of two adjacent portions of the same plate to the same light intensity of the same wave-length or the same time gives the same density under identical conditions of development. This condition is easily satisfied. As will be seen in the sequel, errors are reduced to errors in measurements of length.

A STUDY ON SROTODUSHTI WITH SPECIAL REFERENCE TO ASSESSMENT OF SROTOSHTI LAKSHANA IN ARTAVAVAHA SROTAS THROUGH CLINICAL, BIOCHEMICAL AND RADIOLOGICAL FINDINGS’- SURVEY STUDY

2021 ◽  
Vol 9 (10) ◽  
pp. 2339-2346
Author(s):  
Shivakumari Shivakumari ◽  
Vasudev A Chate ◽  
Shreevastha Shreevastha
Keyword(s):  
Special Reference ◽  
Transport System ◽  
Normal State ◽  
The Body ◽  
Radiological Examination ◽  
Survey Study ◽  
Radiological Findings ◽  
Anatomical Structures ◽  
Conceptual Study

The concept of Srotas and Srotodushti Lakshana has been very scientifically explained in the various context of Ayurveda literature. Detailed Srotas and Srotodushti Lakshana are according to Charaka Samhita Vimansthana assessment of Srotodushti Lakshana can be done by Pratyksha Pramana and in detail explanation. The Srotas play an important role in physiology and the pathogenesis of diseases in normal state; they regulate the physiolo- gy of the body and maintain the anatomical structures of dhatus. The influences of aetiology factors on Srotas can affect pathological manifestations. Considering this fact present study explores various aspects related to the Sro- tas, Srotodushti and Srotodushti Lakshana. Objectives-To assessment of Srotodushti Lakshana in Artavavaha Srotas through Clinical, biochemical, and radiological examination in Artavavaha Srotas. Methodology -The study was conducted under two headings, conceptual and survey study. Conceptual study all the concerned litera- ture were referred and analysed and for survey study, the Artvavaha Sroto Vikara observed and survey through face-face interview. -Hence it is concluded that the knowledge of Srotas is not only used in learning about the anatomy of the transport system of the body but also to understand their physiology and pathology. It can be as- sessed through clinical, biochemical, and radiological findings. Keywords: Srotas, Srotodushti Lakshana, Artavavaha Srotas,

Caudal Fin and Body Movement in the Propulsion of some Fish

1963 ◽  
Vol 40 (1) ◽  
pp. 23-56 ◽  
Author(s):  
RICHARD BAINBRIDGE
Keyword(s):  
Body Movement ◽  
Wave Length ◽  
The Body ◽  
Whole Body ◽  
Tail Region ◽  
Caudal Fin ◽  
A Value ◽  
Total Thrust ◽  
Transverse Movement ◽  
Relationship Of

1. Observations made on bream, goldfish and dace swimming in the ‘Fish Wheel’ apparatus are described. These include: 2. An account of the complex changes in curvature of the caudal fin during different phases of the normal locomotory cycle. Measurements of this curvature and of the angles of attack associated with it are given. 3. An account of changes in area of the caudal fin during the cycle of lateral oscillation. Detailed measurements of these changes, which may involve a 30 % increase in height or a 20 % increase in area, are given. 4. An account of the varying speed of transverse movement of the caudal fin under various conditions and the relationship of this to the changes in area and amount of bending. Details of the way this transverse speed may be asymmetrically distributed relative to the axis of progression of the fish are given. 5. An account of the extent of the lateral propulsive movements in other parts of the body. These are markedly different in the different species studied. Measurements of the wave length of this movement and of the rate of progression of the wave down the body are given. 6. It is concluded that the fish has active control over the speed, the amount of bending and the area of the caudal fin during transverse movement. 7. The bending of the fin and its changes in area are considered to be directed to the end of smoothing out and making more uniform what would otherwise be an intermittent thrust from the oscillating tail region. 8. Some assessment is made of the proportion of the total thrust contributed by the caudal fin. This is found to vary considerably, according to the form of the lateral propulsive movements of the whole body, from a value of 45% for the bream to 84% for the dace.

The continuous absorption of light in alkali-metal vapours

1953 ◽  
Vol 219 (1136) ◽  
pp. 89-101 ◽  
Keyword(s):  
Cross Section ◽  
Alkali Metals ◽  
Theoretical Calculations ◽  
Wave Length ◽  
Energy Difference ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Sodium Vapour ◽  
Good Agreement ◽  
Dipole Length

The first section of this paper is an account of some experiments on the absorption of light in sodium vapour from the series limit at 2412 Å to about 1600 Å (an energy difference of 2·6 eV). The absorption cross-section at the limit is 11·6 ± 1·2 x 10 -20 cm 2 . The cross-section decreases giving a minimum of 1·3 ± 0·6 x 10 -20 cm 2 at 1900 Å and then increases to 1600 Å. A theoretical calculation by Seaton based on the dipole-length formula gives good agreement with the experiments at the series limit and also correctly predicts the wave-length for the minimum, but it predicts a significantly lower absorption at the minimum. The experiments described in the first section of the paper conclude a series on the absorption of light in the alkali metals. The second section consists of a general discussion of the results of these experiments and of their relation to theoretical calculations. There is good agreement between theory and experiment except in regard to the magnitude of the absorption at the minimum.

Histochemical observations on apothecia, permanently vegetative hyphae, and sclerotia of Pyronema domesticum with special reference to light

1981 ◽  
Vol 59 (9) ◽  
pp. 1726-1737 ◽  
Author(s):  
Elizabeth Moore-Landecker
Keyword(s):  
Special Reference ◽  
Potato Dextrose Agar ◽  
Constant Light ◽  
Inorganic Salts ◽  
Histochemical Tests ◽  
Excessive Accumulation

The Discomycete, Pyronema domesticum (Sow. ex Gray) Saccardo was cultured on an inorganic salts medium, as well as on potato dextrose agar (PDA), and exposed to different light regimens. Permanently vegetative hyphae were obtained on PDA cultures illuminated with cycles of 12 h light: 12 h darkness, while abnormal confluent padlike apothecia were formed on PDA in constant light and sclerotia were formed in PDA cultures that were incubated in the dark. Apothecia were formed on the inorganic salts medium and exposed to different light regimens that favored either overall apothecial development or primarily favored development of the ascogenous or sterile system. Histochemical tests were conducted on permanently vegetative hyphae, sclerotia, and apothecia to localize glycogen, carbohydrates, mucilage, protein, DNA, RNA, lipids, and carotenes. Exposure to light stimulated synthesis of DNA, lipid, glycogen, and other carbohydrates. Favorable development of morphologically normal ascogenous hyphae and asci was positively correlated with moderate to high levels of DNA, RNA, protein, and PAS-positive substances (excluding glycogen). Conversely, favorable development of the morphologically normal sterile system was not positively correlated with higher levels of any components, but excessive accumulation of glycogen was associated with its unfavorable, limited development. Massive accumulations of protein, phospholipids, DNA, glycogen, mucilage, and other carbohydrates were observed in the nonsporulating asci in cultures maintained in the dark for 4 days before being exposed to constant light, or in the permanently vegetative hyphae.

scholarly journals The Development and Structure of the Anterior Region of the Body in the Sabellariidae, with special reference to Phragmatopoma californica

1952 ◽  
Vol s3-93 (24) ◽  
pp. 435-452
Author(s):  
R. PHILLIPS DALES
Keyword(s):  
Special Reference ◽  
Larval Development ◽  
The Body ◽  
Anterior Region ◽  
Single Pair ◽  
Phragmatopoma Californica

Attention is drawn to the confusion which has been caused by the loose terminology of the anterior appendages in polychaetes, and more exact connotations are proposed. As the prostomium can be recognized as a comparable unit throughout the Polychaeta, a consideration of its constitution is deferred. In the present paper the development and constitution of the anterior region of the sabellariid worms are considered. The larval development of Phragmatopoma californica (representing the most highly advanced genus) is described, and the structure of the adult of this species is compared with that of species belonging to other genera. It is concluded that the opercular stalk arises mainly from the first segment; that the opercular paleae represent the notochaetae of the first two segments, and that the oral tentacles and the building organ are also developed from the first segment. The prostomium bears a single pair of tentacles.

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